1. Field of the Invention
The field of art to which this invention relates is structural elements, and more particularly to lightweight structural elements having a cavity in which a non-compressible material is disposed resulting in a rigid structure and/or one capable of vibration damping.
2. Description of the Related Art
It is highly desirable to build high speed machinery which are very accurate with structural elements that are light weight, have a high degree of stiffness, and have high internal damping characteristics. This is in fact the case for any product that is subjected to internally and/or externally induced vibrational excitation. With such structural elements, one can then design machines, structures, and other similar devices that are very accurate, that are lighter, and that can operate at higher speeds. This leads to a significant increase in performance.
In the prior art, when vibration becomes a factor, designers had the option of either adding various combinations of mass and viscoelastic material to the structure to employ a passive damper or employ some type of active damping device, such as a piezoelectric device. While the prior art passive damping devices have their advantages, they suffer from the disadvantage of greatly increasing the weight of the structure. This results in a reduction in the attainable speed of the machine or device. Active dampers, on the other hand, are usually lighter but greatly increase the cost of the machine as well as the cost of its operation.
For the above reasons, there is a need in the art for a low weight, low cost structural element that is very rigid and has high internal damping.